Observing Apparent Nonuniform Sensitivity Enhancements in Dynamic Nuclear Polarization Solid-State NMR Spectra of Polymers
| Autor: | Trang N. T. Phan, Pierre Thureau, Stéphane Viel, Gilles Casano, Olivier Ouari, Fabio Ziarelli, Fabien Aussenac, Didier Gigmes, Giulia Mollica, Paul Tordo, Dao Le |
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| Přispěvatelé: | Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Bruker Biospin SA, Wissembourg |
| Rok vydání: | 2022 |
| Předmět: |
chemistry.chemical_classification
Range (particle radiation) Polymers and Plastics Chemistry Radical Physics::Medical Physics Organic Chemistry Analytical chemistry 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Spectral line 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Solid-state nuclear magnetic resonance Materials Chemistry Magic angle spinning [CHIM]Chemical Sciences 0210 nano-technology Polarization (electrochemistry) Methyl group |
| Zdroj: | ACS Macro Letters ACS Macro Letters, Washington, D.C : American Chemical Society, 2014, 3 (9), pp.922-925. ⟨10.1021/mz500459p⟩ ACS Macro Letters, 2014, 3 (9), pp.922-925. ⟨10.1021/mz500459p⟩ |
| ISSN: | 2161-1653 |
| Popis: | International audience; High-field dynamic nuclear polarization (DNP)may enhance the sensitivity of solid-state NMR experimentson a wide range of systems, including synthetic polymers,owing to the transfer of electron spin polarization from radicalsto nuclei upon microwave irradiation (usually at cryogenictemperatures). Provided that the radicals are homogeneouslydispersed in the sample, a uniform DNP enhancement isexpected for all the signals in the 13C cross-polarization magicangle spinning (CPMAS) spectrum. Here, we show that, in thecase of methyl group containing polymers, a change in thecross-polarization (CP) dynamics induced by the moderate increase in sample temperature due to microwave irradiation maylead to the observation of apparent nonuniform enhancements in the DNP-enhanced 13C CPMAS spectra. This peculiarbehavior should be accounted for when measuring 13C CP DNP enhancements on polymer materials, especially forheterogeneous polymer samples (for which truly nonuniform DNP enhancements could potentially be detected), or whenquantitative results are sought. |
| Databáze: | OpenAIRE |
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